Medical device

Abstract

The purpose of the present invention is to provide a medical instrument that is capable of achieving enhanced sliding properties with respect to a device, such as a guide wire to be inserted into an inner cavity, while maintaining flexibility.　The medical instrument 1 comprises: a hollow coil body 101 which is formed by spirally winding a winding wire 101w; and a cladding member 201 with which the winding wire 101w of the coil body 101 is covered. The cladding member 201 comprises: an outer cladding 201A that covers the outer circumferential surface of the coil body 101; and an inner cladding 201B that covers the inner circumferential surface of the coil body 101 and that is coupled to the outer cladding 201A through intervals between adjacent turns of the winding wire of the coil body 101. The inner cladding 201B has a protrusion 201t that protrudes toward the radially inner side of the coil body 101 beyond a common inscribed line 101k of the winding wire 101w in the long axis direction of the coil body 101. The protrusion 201t is formed in a substantially annular shape around the long axis of the coil body 101 and is disposed intermittently in the long axis direction of the coil body 101.

Description

Technical Field

[0001] The present invention relates to medical instruments.

Background Art

[0002] For example, as instruments for treating affected parts in body cavities or directly injecting drugs into body cavities, medical instruments such as dilators and catheters are known.

[0003] Such medical instruments are, for example, delivered to the treatment site while being guided by a guide wire previously inserted into the body cavity. Therefore, the above medical instruments are required to have high slidability with respect to the guide wire so that they can smoothly advance and retreat in the body cavity along the guide wire inserted through their inner cavities.

[0004] As a means for enhancing such slidability, for example, a medical instrument (catheter tube) has been proposed in which an inner layer tube of a thermoplastic resin is provided inside a braid formed of metal wires, and fine irregularities are formed on the inner surface of this inner layer tube to reduce the frictional resistance with a guide wire or the like (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the medical instruments as described above, although they have high slidability with respect to the guide wire, since the entire braid is covered with a thermoplastic resin, the flexibility of the medical instrument tends to decrease due to an increase in rigidity. Therefore, when inserting the medical instrument into a curved body cavity, there is a risk of causing a decrease in followability to the body cavity and hindering smooth progress.

[0007] The present invention has been made based on the above circumstances, and an object thereof is to provide a medical instrument capable of enhancing slidability with respect to a device such as a guide wire inserted into a lumen while maintaining flexibility.

Means for Solving the Problems

[0008] Some aspects of the present disclosure are (1) A medical instrument including a hollow coil body in which a winding is spirally wound, and a covering member that covers the winding of the coil body, wherein the covering member has an outer covering portion that covers the outer peripheral surface of the coil body and an inner covering portion that covers the inner peripheral surface of the coil body and is connected to the outer covering portion via between adjacent windings of the coil body, the inner covering portion has a protruding portion that protrudes radially inward of the coil body more than a common internal tangent of the winding in the longitudinal axis direction of the coil body, the protruding portion is formed in a substantially annular shape around the longitudinal axis of the coil body and is intermittently arranged along the longitudinal axis direction of the coil body, and is characterized by a medical instrument, (2) The medical instrument according to (1) above, including a protruding portion whose length in the longitudinal axis direction is 2 times or more the pitch of adjacent windings, (3) The medical instrument according to (1) or (2) above, wherein the protruding portion is curved convexly toward the radially inner side of the coil body, and (4) The outer peripheral surface of the coil body is provided with a spiral convex portion that protrudes radially outward of the coil body, the spiral convex portion has a gap along the longitudinal axis direction of the coil body, and is the medical instrument according to any one of (1) to (3) above.

[0009] In this specification, the "tip side" refers to the direction along the long axis direction of the coil body, which means the direction in which the medical instrument advances deeper into the body cavity (distal direction). Also, the "proximal side" refers to the direction along the long axis direction of the coil body, which is the direction opposite to the tip side (proximal direction). Further, the "tip" indicates the end portion on the tip side at any member or part, and the "proximal end" indicates the end portion on the proximal side at any member or part, respectively. Also, the "winding wire" means a linear member wound in a spiral shape to form the coil body. Further, the "substantially annular" is a concept including both an annular shape and a spiral shape. Also, "the protrusions are intermittently arranged" means that in any cross-section including the long axis of the coil body, the protrusions are not continuous over the entire inner covering portion along the long axis direction.

Advantages of the Invention

[0010] The present invention can provide a medical instrument capable of enhancing the slidability with respect to a device such as a guide wire inserted into a lumen while maintaining flexibility.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3E

Figure 3F

Figure 3G

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0012] The medical instrument of the present disclosure is a medical instrument including a hollow coil body in which a winding is spirally wound and a covering member that covers the winding of the coil body. The covering member has an outer covering portion that covers the outer peripheral surface of the coil body and an inner covering portion that covers the inner peripheral surface of the coil body and is connected to the outer covering portion via between adjacent windings of the coil body. The inner covering portion has a protruding portion that protrudes radially inward of the coil body more than a common internal tangent of the winding in the longitudinal direction of the coil body. The protruding portion is formed in a substantially annular shape around the longitudinal axis of the coil body and is intermittently arranged along the longitudinal direction of the coil body.

[0013] Hereinafter, the first to fourth embodiments will be described with reference to the drawings. However, the present disclosure is not limited only to the embodiments described in the drawings. Also, the dimensions of each part shown in the drawings are the dimensions shown for facilitating the understanding of the implementation content and do not necessarily correspond to the actual dimensions. In each cross-sectional view, the outer covering portion and the inner covering portion are represented in one region for convenience.

[0014] [First Embodiment] Figures 1 and 2 are schematic diagrams showing the first embodiment. In this embodiment, the catheter 11 will be described as an example of the medical device 1. As shown in FIG. 1, the medical device 1 (catheter 11) is generally composed of a coil body 101, a covering member 201, a tip chip 301, and a base 401. In FIG. 1, the coil body 101, the covering member 201, and the tip chip 301 are shown in cross-sectional shape, and the base 401 is shown in side view shape.

[0015] The coil body 101 is a hollow member having a lumen 101h inside, with the winding 101w spirally wound around the long axis of the catheter 11 at a pitch P. Specifically, the coil body 101 can adopt, for example, a single-strand coil body formed by winding a single wire, a multi-strand coil body formed by winding two or more wires in multiple strands, or a combination of a single-strand coil and a multi-strand coil.

[0016] Examples of the winding 101w include a single wire (a single line) and a stranded wire (a bundle of wire groups formed by twisting two or more single wires together in advance).

[0017] Since the material of the winding constituting the coil body 101 is inserted into the body cavity, it preferably has antithrombotic, flexible, and biocompatible properties. Examples of the material of the winding 101w constituting the coil body 101 include resin materials such as polyamide resin, polyolefin resin, polyester resin, polyurethane resin, silicone resin, and fluororesin; and metal materials such as stainless steel (SUS316, etc.) and superelastic alloy (nickel-titanium alloy, etc.).

[0018] The covering member 201 is a member that covers the winding 101w of the coil body 101. As shown in FIG. 2, the covering member 201 can be configured to have, for example, an outer covering portion 201A and an inner covering portion 201B.

[0019] The outer covering portion 201A is a part that covers the outer peripheral surface (the surface facing the outside) of the coil body 101. The outer covering portion 201A may cover only a part of the outer peripheral surface of the coil body 101, or may cover the whole. The surface (outer peripheral surface) of the outer covering portion 201A may be formed flat, for example, so as not to damage the tissue of the body cavity wall into which the catheter 11 is inserted.

[0020] The inner covering portion 201B is a part that covers the inner peripheral surface (the surface facing the inner cavity 101h) of the coil body 101 and is connected to the outer covering portion 201A through the space between adjacent turns 101w of the coil body 101. Specifically, for example, the inner covering portion 201B is integrally connected to the outer covering portion 201A through a gap 101g formed between adjacent turns 101w that make up the coil body 101. This gap 101g may be formed between all adjacent turns 101w, or may be formed only between some adjacent turns 101w. Also, the inner covering portion 201B and the outer covering portion 201A may be connected at all the gaps 101g, or may be connected at only some of the gaps 101g.

[0021] Examples of the materials constituting the above-described outer covering portion 201A and inner covering portion 201B include resin materials such as polyamide, polyamide elastomer, polyester, polyurethane, and polytetrafluoroethylene (PTFE).

[0022] Note that the material constituting the outer covering portion 201A and the material constituting the inner covering portion 201B may be the same or different. When the outer covering portion 201A and the inner covering portion 201B are made of the same material, the outer covering portion 201A and the inner covering portion 201B can be firmly connected by improving compatibility. Also, when polytetrafluoroethylene (PTFE) is used for the inner covering portion 201B, the slidability with a guide wire or the like inserted into the inner cavity 101h can be further enhanced.

[0023] As shown in Fig. 2, the surface (inner peripheral surface) of the inner covering portion 201B is formed to have a protruding portion 201t that protrudes radially inward of the coil body 101 from the common inscribed line 101k of the winding 101w in the long axis direction of the coil body 101. The protruding portion 201t is formed, for example, in a substantially annular shape around the long axis of the coil body 101 and can be arranged intermittently along the long axis direction of the coil body 101.

[0024] Here, as a specific mode in which the protruding portions 201t are arranged intermittently along the long axis direction, for example, a mode in which two or more protruding portions 201t formed in an annular shape around the long axis of the coil body 101 are arranged while being separated in the long axis direction, a mode in which the protruding portions 201t formed along the gap 101g are arranged in a spiral shape while being separated in the long axis direction, etc. can be mentioned. When the protruding portion 201t is formed in a spiral shape, the protruding portion 201t may be composed of a single continuous portion along the gap 101g or may be composed of two or more independent portions. The pitch in the long axis direction between adjacent protruding portions 201t arranged intermittently may be regular (for example, a constant pitch) or irregular.

[0025] The protruding portion 201t of the present embodiment is formed so as to protrude to the inside (lower side of the paper surface) of the common inscribed line 101k of the winding 101w, be independent (separated) from each other in the long axis direction of the coil body 101, and be continuous in a spiral shape along the gap 101g of the winding 101w in the spiral direction of the coil body 101.

[0026] The shape of the surface (inner peripheral surface) of the protruding portion 201t is not particularly limited as long as the effects of the present disclosure are not impaired. In the present embodiment, the protruding portion 201t is formed to be convexly curved toward the radially inner side of the coil body 101. Thereby, the contact resistance between a device such as a guide wire inserted inside and the inner covering portion 201B can be reduced, and the slidability of the inserted device can be further enhanced.

[0027] Here, a method for forming the covering member 201 will be described. Note that the method for forming the covering member 201 is not limited to only the following method. Here, a method for forming the covering member 201 using a heat-shrinkable tube will be described, where the outer covering portion 201A and the inner covering portion 201B are made of the same material.

[0028] First, using the coil body 101 formed by the winding 101w, cover the entire outer peripheral surface of the coil body 101 with a resin tube Z1 for forming the covering member (see Fig. 3A). Next, cover the entire outer peripheral surface of the resin tube Z1 with a heat-shrinkable tube Z2 (see Fig. 3B). As a result, a three-layer structure T composed of, in order from the inside, the coil body 101, the resin tube Z1, and the heat-shrinkable tube Z2, as shown in Fig. 3C, is formed. Note that a mandrel ZM having a predetermined outer diameter may be inserted in advance into the inner cavity of the coil body 101 constituting the three-layer structure T so that the coil body 101 after the formation of the covering member 201 can secure a lumen 101h having a predetermined inner diameter (see the mandrel ZM illustrated by the phantom line in Figs. 3A to 3F).

[0029] As the heat-shrinkable tube Z2, one that shrinks at a predetermined pressure at a temperature at which the material of the resin tube Z1, that is, the material constituting the covering member 201, softens or melts (a temperature equal to or higher than the glass transition point) can be selected. Examples of the material constituting the heat-shrinkable tube Z2 include synthetic resins such as polyolefin-based resins, polyester-based resins, nylon-based resins, silicone-based resins, and fluorine-based resins, although it depends on the material of the covering member 201. The material of the heat-shrinkable tube Z2 may be used alone or in combination of two or more.

[0030] Next, the three-layer structure T is put into a heating furnace F (see Fig. 3D) and heated at a predetermined temperature for a predetermined time. Here, the predetermined temperature and the predetermined time refer to a temperature and a time at which the material constituting the resin tube Z1 is softened or melted and a part of the softened or melted resin tube Z1 due to the shrinkage of the heat-shrinkable tube Z2 is extruded into the inner cavity of the coil body 101 through the gap 101g to form the protruding portion 201t.

[0031] As shown in FIG. 3E, the heated three-layer structure T gradually reduces its diameter due to the shrinking force of the heat-shrinkable tube Z2 located on the outermost periphery, and a part of the softened or melted resin tube Z1 is pushed into the inner cavity of the coil body 101 through the gap 101g, thereby forming the protruding portion 201t. At this time, the surface (inner peripheral surface) of the protruding portion 201t has a convexly curved shape toward the inner side in the radial direction of the coil body 101 due to the surface tension of the softened or melted resin.

[0032] Next, after cooling the heated three-layer structure T to room temperature, as shown in FIG. 3F, by removing the heat-shrinkable tube Z2 (and the mandrel ZM), a covering member 201 covering the coil body 101 as shown in FIG. 3G is formed. Among the formed covering member 201, the portion covering the outer peripheral surface of the coil body 101 becomes the outer covering portion 201A, and the portion covering the inner peripheral surface of the coil body 101 becomes the inner covering portion 201B.

[0033] The tip chip 301 is a member provided at the tip of the catheter 11. Specifically, for example, the tip of the tip chip 301 may be formed in a rounded shape toward the tip side so that the catheter 11 can easily move in the body cavity. The tip chip 301 has an opening 301a at the tip and an inner cavity 301h communicating with the inner cavity 101h of the coil body 101.

[0034] As the material constituting the tip chip 301, it is preferably flexible so as to have antithrombogenicity and biocompatibility and to mitigate the impact on the body cavity or the like. Examples of such materials include resin materials such as polyurethane and polyurethane elastomer.

[0035] As a method of joining the tip chip 301 and the coil body 101, for example, a method of welding or adhering the base end portion of the tip chip 301 to the tip end portion of the winding 101w constituting the coil body 101 with an adhesive or the like can be mentioned.

[0036] The base 401 is a member that an operator operates the catheter 11. The base 401 is connected to the proximal end portion of the coil body 101. The base 401 has, for example, an opening 401a at the proximal end and an inner cavity 401h that communicates with the inner cavity 101h of the coil body 101. The shape of the base 401 is not particularly limited as long as the effects of the present invention are not impaired, and for example, it can be formed into a shape that is easy for the operator to operate.

[0037] The lumen M is formed by the inner cavity 301h of the tip tip 301, the inner cavity 101h of the coil body 101, and the inner cavity 401h of the base 401. A device such as a guide wire is inserted into the lumen M.

[0038] Next, the usage mode of the medical instrument 1 will be described. Here, the medical instrument 1 (catheter 11) is a guiding catheter (hereinafter, also referred to as "guiding catheter 11"), and a procedure for expanding a stenosis occurring in the coronary artery of the heart while inserting a balloon catheter into the lumen M of the guiding catheter will be exemplified.

[0039] Prior to the use of the guiding catheter 11, first, the guide wire A is inserted into the blood vessel, and its tip is advanced to near the coronary artery inlet of the heart. Next, the proximal end of the guide wire A is inserted into the opening 301a of the guiding catheter 11, and the guiding catheter 11 is advanced while being pushed into the blood vessel along the guide wire A so that the tip reaches the coronary artery inlet of the heart. At this time, the guiding catheter 11 is fed while following the curvature of the blood vessel.

[0040] Next, after removing the guide wire A from the body, a thin guide wire B for the balloon catheter is inserted into the guiding catheter 11 through the opening 401a, and the tip of the guide wire B is advanced through the guiding catheter 11 to reach a position where it passes through the stenosis. Next, the proximal end of the guide wire B is inserted into the tip opening of the balloon catheter, and the balloon catheter is pushed along the guide wire B to the inside of the stenosis. Next, the balloon of the balloon catheter is inflated to expand the stenosis. After the stenosis is expanded, the balloon catheter, the guide wire B, and the guiding catheter 11 are removed from the body in this order, and the procedure using the guiding catheter 11 is completed.

[0041] As described above, since the medical instrument 1 (catheter 11) has the above configuration, it is possible to reduce the contact resistance between a device such as a guide wire inserted inside and the inner coating portion 201B, and while maintaining the flexibility of the coil body 101, it is possible to enhance the slidability with respect to the device inserted into the lumen 101h. It is presumed that the coil body 101 can maintain flexibility because when an external force in a direction orthogonal to the long axis direction is applied to the catheter 11, the coil body is likely to bend in the orthogonal direction starting from the portion between adjacent protrusions that are formed in a substantially annular and intermittent manner and are spaced apart from each other (the formation of the bellows-shaped protrusions suppresses an increase in the rigidity of the catheter).

[0042] [Second Embodiment] FIG. 4 is a schematic cross-sectional view showing an enlarged part of the second embodiment. The medical instrument 1 (catheter 12) is generally composed of a coil body 101, a covering member 202, a tip chip 301 (not shown), and a base 401 (not shown). The catheter 12 is different from the first embodiment in that it includes a covering member 202. Since the coil body 101, the tip chip 301, and the base 401 are the same as those in the first embodiment, the same reference numerals are given to the same parts and their detailed description is omitted. In addition, the configuration of the covering member other than the configuration of the covering member 202 shown below is the same as that in the first embodiment.

[0043] The covering member 202 is a member that covers the winding 101w of the coil body 101. The covering member 202 can be configured to have, for example, an outer covering portion 202A and an inner covering portion 202B. The outer covering portion 202A is a portion that covers the outer peripheral surface of the coil body 101. The inner covering portion 202B is a portion that covers the inner peripheral surface of the coil body 101 and is connected to the outer covering portion 202A via the space between adjacent windings 101w of the coil body 101. The inner covering portion 202B has a protruding portion 202t that protrudes radially inward of the coil body 101 more than the common internal tangent 101k of the windings 101w in the major axis direction of the coil body 101. The protruding portion 202t is formed in a substantially annular shape around the major axis of the coil body 101 and is intermittently arranged along the major axis direction of the coil body 101.

[0044] The length of the protruding portion 202t in the major axis direction may be formed to include a protruding portion having a length of at least twice the pitch of the adjacent windings 101w. In the present embodiment, as shown in FIG. 4, an inner covering portion 202B including a protruding portion 202t having a length L in the major axis direction of approximately three times the pitch P of the winding 101w is illustrated. Further, in the catheter 12, each of the protruding portions 202t is formed to be convexly curved toward the radially inner side of the coil body 101. Further, the protruding portions 202t are intermittent along the major axis direction of the coil body 101, that is, in the major axis direction of the coil body 101, the adjacent protruding portions 202t are arranged so as to be separated from each other.

[0045] As a method for forming the inner covering portion 202B, for example, in the method for forming the covering member 202 described in the first embodiment, while adjusting the pressure during heat shrinkage by appropriately selecting the type of heat shrinkable tube Z2 used for the three-layer structure T, a method of heating the three-layer structure T at a predetermined temperature for a predetermined time or the like can be adopted. Further, the material constituting the covering member 202 may be appropriately selected to adjust the fluidity during heating. Thereby, the amount of the softened or melted resin tube Z1 extruded into the inner cavity through the gap 101g can be controlled, and as a result, the protruding portion 202t having a desired length can be formed. Note that due to the surface tension of the softened or melted resin, the protruding portion 202t that is convexly curved toward the inner side in the radial direction of the coil body 101 is formed.

[0046] As described above, the catheter 12 is formed such that the length L of the protruding portion 202t in the long axis direction includes a protruding portion that is at least twice the pitch P of the adjacent windings 101w. Therefore, by covering the entire winding 101w adjacent to the gap 101g with the inner covering portion 202B, even if the inner covering portion 202B and the outer covering portion 202A are separated for some reason, it is possible to reduce the detachment of the protruding portion 202t from the winding 101w.

[0047] [Third Embodiment] FIG. 5 is a schematic cross-sectional view showing an enlarged part of the third embodiment. As shown in FIG. 5, the medical instrument 1 (catheter 13) is schematically composed of a coil body 101, a base layer 503, a covering member 202, a tip chip 301 (not shown), and a base portion 401 (not shown). The catheter 13 is different from the second embodiment in that it includes a base layer 503. Note that the coil body 101, the covering member 202, the tip chip 301, and the base portion 401 are the same as those in the second embodiment, so the same reference numerals are given to the same parts and their detailed description is omitted.

[0048] The base layer 503 is a layered part arranged to be in contact with the winding 101w and the covering member 202, and is provided to enhance the adhesion between the winding 101w and the covering member 202.

[0049] Examples of the material constituting the underlying layer 503 include acrylic resins, but other resins such as urethane resins and epoxy resins can also be selected.

[0050] The thickness of the underlying layer 503 is preferably about 1 μm, for example, but the film thickness can be appropriately changed according to the specifications.

[0051] As described above, since the catheter 13 is provided with the underlying layer 503 so as to be in contact with the winding 101w and the covering member 202, the adhesion between the winding 101w and the covering member 202 can be enhanced. Even if the inner covering portion 202B and the outer covering portion 202A are separated for some reason, it is possible to more reliably reduce the detachment of the protruding portion 202t from the winding.

[0052] [Fourth Embodiment] FIGS. 6 and 7 are schematic views showing the fourth embodiment. In this embodiment, the dilator 14 is exemplified as the medical instrument 1 for explanation. As shown in FIG. 6, the medical instrument 1 (dilator 14) is generally composed of a coil body 104, a spiral convex portion 604, a covering member 204, and a base portion 404. The dilator 14 is different from the first embodiment in that it includes a coil body 104, a spiral convex portion 604, a covering member 204, and a base portion 404. The configurations of the coil body, the covering member, and the base portion other than the configurations of the coil body 104, the covering member 204, and the base portion 404 shown below are the same as those of the first embodiment. In FIG. 6, the tip portion of the dilator 14 is shown as a cross-sectional shape, and the base end portion of the dilator 14 is shown as a side surface shape.

[0053] The coil body 104 is a hollow member in which the winding 104w is wound in a spiral shape. The coil body 104 can be formed, for example, by winding the winding 104w around the long axis of the dilator 14 in a spiral shape with a pitch P. The coil body 104 has a lumen 104h with an opening 104a at the tip.

[0054] The coil body 104 of this embodiment has a tapered portion 104B, a tip portion 104A, and a main body portion 104C. The tapered portion 104B is a portion where the outer diameter at the tip is smaller than the outer diameter at the base. The tip portion 104A is a portion where the base is located at the tip of the tapered portion 104B and extends toward the tip side in the axial direction of the tapered portion 104B with a constant outer diameter. The main body portion 104C is a portion where the tip is located at the base of the tapered portion 104B and extends toward the base side in the axial direction of the tapered portion 104B with a constant outer diameter.

[0055] The spiral convex portion 604 is provided on the outer peripheral surface of the coil body 104 and is a member that protrudes radially outward from the coil body 104. The spiral convex portion 604 has a gap 604g in adjacent portions along the long axis direction of the coil body 104. The spiral convex portion 604 may be continuously formed or intermittently formed along the long axis direction. Also, the spiral convex portion 604 may be a single convex portion or a multi-strand convex portion.

[0056] The spiral convex portion 604 is provided at least on the outer periphery of the tapered portion. In this embodiment, the spiral convex portion 604 is provided on the outer peripheries of the tip portion 104A, the tapered portion 104B, and the main body portion 104C.

[0057] The spiral convex portion 604 can be formed, for example, by winding a wire 604w (single wire) around the outer periphery of the coil body 104.

[0058] Since the spiral convex portion 604 is inserted into the body cavity, the material constituting the spiral convex portion 604 preferably has antithrombotic properties, flexibility, and biocompatibility. Examples of the material constituting the spiral convex portion 604 include resin materials such as polyamide resin, polyolefin resin, polyester resin, polyurethane resin, silicone resin, and fluororesin; and metal materials such as stainless steel (SUS316, etc.) and superelastic alloy (nickel-titanium alloy, etc.).

[0059] As a method for joining the coil body 104 and the spiral convex portion 604, for example, a method of brazing both at an appropriate position (contact portion, end portion, etc.) with a brazing material, a method of welding, a method of bonding with an adhesive, etc. can be mentioned.

[0060] The covering member 204 is a member that covers the winding 104w of the coil body 104. As shown in FIG. 7, the covering member 204 can be configured to have, for example, an outer covering portion 204A and an inner covering portion 204B. The outer covering portion 204A is a portion that covers the outer peripheral surface of the coil body 104. The inner covering portion 204B is a portion that covers the inner peripheral surface of the coil body 104 and is connected to the outer covering portion 204A via the space between adjacent windings 104w of the coil body 104. The inner covering portion 204B has a protruding portion 204t that protrudes radially inward of the coil body 104 from the common internal tangent 104k of the windings 104w in the long axis direction of the coil body 104. The protruding portion 204t is formed in a substantially annular shape around the long axis of the coil body 104 and is intermittently arranged along the long axis direction of the coil body 104.

[0061] The outer covering portion 204A may be provided so as to cover the spiral convex portion 604, or may be provided so as not to cover the spiral convex portion 604. When the outer covering portion 204A covers the spiral convex portion 604, the portion of the spiral convex portion 604 covered by the outer covering portion 204A may be a part of the outer peripheral surface of the spiral convex portion 604, or may be all of it.

[0062] The outer covering portion 204A of the present embodiment is provided so as to cover at least a part of the outer peripheral surface of the spiral convex portion 604 while straddling the coil body 104 and the spiral convex portion 604. Thereby, the joining strength between the coil body 104 and the spiral convex portion 604 can be further increased.

[0063] The base 404 is a member for an operator to operate the dilator 14. The base 404 is connected to the proximal end portion of the coil body 104 and the proximal end portion of the spiral convex portion 604. The base 404 has, for example, an opening 404a at the proximal end and an inner cavity 404h communicating with the inner cavity 104h of the coil body 104. The shape of the base 404 is not particularly limited as long as the effects of the present invention are not impaired, and it can be formed into a shape that is easy for the operator to operate, for example.

[0064] The lumen N is formed by the inner cavity 104h of the coil body 104 and the inner cavity 404h of the base 404. A device such as a guide wire is inserted into the lumen N, for example.

[0065] Next, the usage mode of the medical instrument 1 (dilator 14) will be described. Here, a procedure of forming a hole (a portion to be dilated) in the wall of an organ such as the gastric wall and dilating the hole formed using the dilator 14 will be exemplified.

[0066] First, a hole (a portion to be dilated) is formed by puncturing the wall of the organ using an introduction needle (not shown). Next, after inserting a guide wire (not shown) into the inner cavity of the introduction needle, the introduction needle is removed from the body along the guide wire.

[0067] Next, the proximal end of the guide wire is inserted into the inner cavity 104h through the opening 104a of the dilator 14, and the distal end of the dilator 14 is pushed forward until just before the formed hole. Next, the distal end portion 104A of the coil body 104 is inserted into the hole, and the dilator 14 is advanced so that the tapered portion 104B abuts against the inner wall of the hole. Next, while rotating the base 404, the spiral convex portion 604 provided on the outer peripheral surface of the tapered portion 104B is bitten into the inner wall of the hole. At this time, due to the screw action of the spiral convex portion 604, the coil body 104 advances, and the hole is gradually expanded by the outer peripheral surface of the tapered portion 104B. When the proximal end of the tapered portion 104B passes through the hole, the hole is expanded to a size corresponding to the outer diameter of the proximal end of the tapered portion 104B (= the outer diameter of the main body portion 104C).

[0068] When expanding the hole by operating the base 404, the rotation of the coil body 104 and the linear pushing in the long axis direction may be used in combination.

[0069] Next, after the hole expansion is completed, the dilator 14 and the guide wire are removed from the body in this order, and the procedure using the dilator 14 is completed.

[0070] As described above, in the dilator 14, a spiral convex portion 604 protruding radially outward of the coil body 104 is provided on the outer peripheral surface of the coil body 104, and the spiral convex portion 604 has a gap 604g along the long axis direction of the coil body 104. Therefore, due to the screw action of the spiral convex portion 604 generated as the coil body 104 rotates, the advancement and retraction of the dilator 14 in the body cavity can be easily and surely performed.

[0071] Further, in the dilator 14, the coil body 104 has a tapered portion 104B whose outer diameter at the tip is smaller than the outer diameter at the base end, and the spiral convex portion 604 is provided on the outer periphery of the tapered portion 104B. Therefore, in combination with the screw action of the spiral convex portion 604, the portion to be expanded (drilled hole, stenosis portion, etc.) can be easily expanded.

[0072] Note that the present invention is not limited to the configuration of the above-described embodiments, is indicated by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims. A part of the configuration of the above-described embodiments may be deleted, replaced with other configurations, or other configurations may be added to the configuration of the above-described embodiments.

[0073] For example, in the first to third embodiments described above, the catheters 11, 12, 13 having the tip chip 301 and the base 401 were described. However, a catheter that does not have a tip chip and / or a base may also be used.

[0074] In the fourth embodiment described above, the dilator 14 in which the coil body 104 has a tapered portion 104B and the spiral convex portion 604 is provided on the outer periphery of the tapered portion 104B has been described. However, a medical instrument in which a spiral convex portion is formed on a coil body having no tapered portion (for example, a stepped coil body, a coil body having a constant outer diameter from the tip to the base end, etc.) may also be used. Further, a dilator in which the coil body has a tapered portion and the spiral convex portion is formed only at a portion other than the tapered portion (for example, the tip portion and / or the main body portion) may also be used.

[0075] In the fourth embodiment described above, the dilator 14 in which the spiral convex portion 604 is provided only on the tip side in the major axis direction on the outer peripheral surface of the coil body has been described. However, the spiral convex portion may be provided over the entire major axis direction on the outer peripheral surface of the coil body.

[0076] In the fourth embodiment described above, the dilator 14 provided with the base portion 404 has been described. However, a dilator not provided with a base portion or a dilator provided with a tip chip such as the tip chip 301 may also be used.

Explanation of Reference Numerals

[0077] 1 Medical instrument 11, 12, 13 Catheter 14 Dilator 101, 104 Coil body 101k, 104k Common inscribed line 101w, 104w Winding 104B Tapered portion 201, 202, 204 Coating member 201A, 202A, 204A Outer coating portion 201B, 202B, 204B Inner coating portion 201t, 202t, 204t Protrusion 503 Base layer 604 Spiral convex portion 604g Gap L Length of protrusion P Pitch of winding

Claims

1. A medical device comprising a hollow coil body formed by spirally winding a winding wire so as to have a lumen through which a device such as a guide wire is inserted, and a covering member that covers the winding wire of the coil body, wherein the covering member has an outer covering portion that covers the outer peripheral surface of the coil body and an inner covering portion that covers the inner peripheral surface of the coil body and is connected to the outer covering portion via between adjacent winding wires of the coil body, the inner covering portion has a protruding portion that protrudes radially inward of the coil body more than a common internal tangent of the winding wire in the longitudinal axis direction of the coil body, the protruding portion is formed in a substantially annular shape around the longitudinal axis of the coil body and is intermittently arranged along the longitudinal axis direction of the coil body, the inner covering portion covers only a part of the inner peripheral surface of the coil body. The medical device is characterized by this.

2. A medical device comprising a hollow coil body formed by spirally winding a winding wire so as to have a lumen through which a device such as a guide wire is inserted, and a covering member that covers the winding wire of the coil body, wherein the covering member has an outer covering portion that covers the outer peripheral surface of the coil body and an inner covering portion that covers the inner peripheral surface of the coil body and is connected to the outer covering portion via between adjacent winding wires of the coil body, the inner covering portion has a protruding portion that protrudes radially inward of the coil body more than a common internal tangent of the winding wire in the longitudinal axis direction of the coil body, the protruding portion is formed in a substantially annular shape around the longitudinal axis of the coil body and is intermittently arranged along the longitudinal axis direction of the coil body, the medical device includes a protruding portion whose length in the longitudinal axis direction is equal to or more than twice the pitch of adjacent winding wires.

3. The medical device according to claim 1 or claim 2, wherein the protruding portion is curved convexly toward the radially inner side of the coil body.

4. The outer peripheral surface of the coil body is provided with a spiral convex portion that protrudes radially outward of the coil body, and the spiral convex portion has a gap along the longitudinal axis direction of the coil body. The medical device according to any one of claims 1 to 3.

5. The medical device according to claim 4, wherein the spiral convex portion is formed by winding a wire around the outer periphery of the coil body.

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